The Senate's 58 to 39 vote fell just short of the 60 votes needed to tack on the contentious amendment to a massive defense policy bill. Senators will continue to wade through other provisions of the $680 billion defense authorization bill throughout the week before taking a vote on whether to pass the complete package.

The amendment would have let people with concealed weapons permits carry their guns into other states as long as they followed that state's laws about where concealed weapons are permissible.

Prior to today's vote, the NRA had prevailed on three major gun-rights bills this year, including measures to lift a federal ban on guns in National Parks, allow stored guns to be carried on Amtrak, and to strip the Washington, D.C., City Council's ability to regulate gun ownership.

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Those who disliked the proposal and ultimately won today's fight worried states with stricter gun laws would be trumped by those with more lax requirements if the amendment became law.

"Each state has considered this issue and has decided what is safe for their residents," Sen. Dick Durbin, D-Ill., said today on the Senate floor. For instance, he said some states prohibit abusers of alcohol, those convicted of crimes, and people who haven't completed a gun use training course from carrying a weapon.

"Clearly, large, urban areas merit a different standard than rural areas," Sen. Charles Schumer, D-N.Y., said in a statement earlier this week. "To gut the ability of local police and sheriffs to determine who should be able to carry a concealed weapon makes no sense."

Today, Schumer added that the proposal "directly threatens the safety of millions of New Yorkers," suggesting that people could transport guns in something as simple as a backpack from neighboring Vermont, where requirements are less stringent, and carry them onto the streets of the Bronx or into Central Park.

"Our local police would have their hands tied," Schumer said.

Democrat Arlen Specter of Pennsylvania also opposed the effort.

"From my own experience growing up in Kansas and being District Attorney of Philadelphia, I know states need to prescribe their own rules for carrying a concealed deadly weapon," Specter said Tuesday. "This is the essence of federalism.

"My vote against the Thune Amendment will not limit the constitutional rights of hunters and gun owners," he said. "Pennsylvania already recognizes concealed carry permits from 24 other states where their laws are similar."

But the gun debate was not an issue that cut down party lines, and some thought the legislative climate was ripe for the proposal to advance. Many new Democrats from conservative states are supportive of gun rights. Senate Majority Leader Harry Reid, D-Nev., was among 20 Democrats who voted in favor of the amendment.

Ultimately, the measure was defeated because two veteran Republicans who frequently support gun rights voted against it. Both Indiana's Richard Lugar and Ohio's George were surprise "No" votes. Neither has explained their decision.

Making the case for his amendment this morning, author Sen. John Thune, R-S.D., said, "The visitor must comply with the restrictions of the state they are in." He explained that in South Dakota, for instance, concealed weapons are prohibited at schools or anywhere that sells alcohol.

"It is not, as some have suggested, a preemption of state laws," he added.

There were just two states not slated to be part of the plan: Illinois and Wisconsin do not issue any conceal and carry permits so the amendment wouldn't have affected them. The amendment also did not apply to the District of Columbia.

"Law-abiding South Dakotans should be able to exercise the right to bear arms in states with similar regulations on concealed firearms," Thune said in a Monday statement. "My legislation enables citizens to protect themselves while respecting individual state firearms laws."

Those backing the measure also argued that it's not the people holding permits that Americans need to worry about.

"Few criminals are going to go down to the county courthouse and file a permit," said Virginia Democratic Sen. Jim Webb, who said he has a concealed carry permit himself.

Sen. Lindsey Graham, R-S.C., agreed, saying that those who take the time to go through the steps that many states require of gun permit holders before carrying a concealed weapon are likely the ones who "understand the responsibility that goes with owning it."

"Whatever gun crimes are being committed out, there they're not being committed as an overriding, general rule by the people who have gone through the process of getting a permit to carry a weapon," Graham said.

Protecting Right to Self-Defense or Boon for Killers?

The vote was yet another gun debate that extended beyond the walls of the U.S. Senate. More than 400 mayors took out full page ads in newspapers nationwide opposing the amendment. And families affected by the April 2007 shootings at Virginia Tech ran a full-page ad in Monday's Richmond Times-Dispatch urging Virginia Sens. Webb and Mark Warner not to follow Thune's lead.

"Virginia has seen the worst consequences of guns falling into the wrong hands," the ad from Virginia Tech families says.

"But Congress is now moving a bill that would make Virginia's requirements meaningless by forcing our law enforcement to honor permits from states with weaker rules," it says. "That means that non-Virginians with concealed carry permits issued by any other state would be able to carry concealed handguns into our cities and towns, from Richmond to Norfolk and from Arlington to Blacksburg."

But pressure to support the gun amendment came from another corner of the state. Advocates of Thune's amendment at the NRA's headquarters in Fairfax, Va., asked members to convince senators of the opposite stance, saying, "Now is the time for Congress to recognize that the right to self-defense does not end at state lines."

At the Brady Campaign to Prevent Gun Violence, those fighting for stricter gun laws said three recent shootings by permit holders were reason enough to reject Thune's proposal.

"It is an outrage that in a year thus far defined by gun violence -- from massacres, to the murder of police, to hate crimes -- the U.S. Senate is preparing to consider an amendment that would dramatically weaken federal and state gun laws," the Brady Campaign to Prevent Gun Violence said in a joint statement with Coalition to Stop Gun Violence, Freedom States Alliance, Legal Community Against Violence, States United to Prevent Gun Violence, and Violence Policy Center.

"The practical effect of the amendment would be to reduce concealed carry permit regulations to the lowest common denominator," the groups said.

"The legislation would do nothing less than take state and local gun laws and tear them up," Schumer said today. "The great irony of this amendment is that the pro gun lobby has always said, 'Let the states decide.'"

Republicans were able to stall a bill to give Washington, D.C., a vote in the House by inserting an amendment that would have taken away the city council's right to pass any gun restrictions.

And a provision to allow loaded guns in national parks if allowed by state law was attached to a credit card reform bill.